//A useful program for runners
// Created by qianxun on 17-2-6.
//
#include <stdio.h>
const int S_PER_M = 60;//1分钟的秒数
const int S_PER_H = 3600;//1小时的分钟数
const double M_PER_K = 0.62137;//1公里的英里数
int main(void)
{
    double distk, distm;//跑过的距离（分别以公里和英里为单位）
    double rate;//平均速度（以英里/小时为单位）
    int min, sec;//跑步用时（以分钟和秒为单位）
    int time;//跑步用时（以秒为单位）
    double mtime;//跑1英里需要的时间，以秒为单位
    int mmin, msec;//跑1英里需要的时间，以分钟和秒为单位

    printf("This program converts your time for a metric race\n");
    printf("to a time for running a mile and to your average\n");
    printf("speed in miles per hour.\n");
    printf("Please enter, in kilometers, the distance run.\n");
    scanf("%lf", &distk);//%lf表示读取一个double类型的值
    printf("Next enter the time in minutes and seconds.\n");
    printf("Begin by entering the minutes.\n");
    scanf("%d", &min);
    printf("Now enter the seconds.\n");
    scanf("%d", &sec);

    time = S_PER_M * min + sec;//把时间转换为秒
    distm = M_PER_K * distk;//把公里转换为英里
    rate = distm / time * S_PER_H;//英里/秒X秒/小时 = 英里/小时
    mtime = (double) time / distm;//时间/距离 = 跑1英里所用的时间
    mmin = (int) mtime / S_PER_M;//求出分钟数
    msec = (int) mtime % S_PER_M;//求出剩余的秒数

    printf("You ran %1.2f km (%1.2f miles) in %d min, %d sec.\n",
            distk, distm, min, sec);
    printf("That pace corresponds to running a mile in %d min, ",
            mmin);
    printf("%d sec.\nYour average speed was %1.2f mph.\n", msec, rate);

    return 0;
}